Comparing the cost of an integrated solar roof with a roof and separate solar panels

Otherwise, the comparison may set one square metre of finished covering against one square metre of the photovoltaic module alone.

A similar problem concerns the price per unit of power. In a conventional PV installation, this indicator can help assess the cost of the energy part. With an integrated roof, part of the outlay simultaneously serves to protect the building. Therefore, the cost per kilowatt alone shows neither the full value of the system nor the full expenditure on its construction.

In both variants, include preparation of the substrate, the covering, flashings, drainage and access for the crews. Then add the electrical equipment, cables, protective devices and commissioning. If you are replacing an old roof, dismantling and waste disposal are added to the list. All items should relate to the same scope. It is also worth describing the condition in which the site is handed over, so that both contractors price the same prepared substrate.

Ask for a breakdown of labour and optional elements. A battery storage system, a car charger or extensive monitoring can significantly change the final price. Their presence in only one variant is not a defect of the offer. However, they must be removed from the basic comparison or added to the other variant.

Two installations with a similar rated power may have different production. The orientation of the roof slope, shading and the operating conditions of the modules matter. A joint simulation should use the same weather data and a similar set of losses. It is not enough to compare an optimistic forecast from one offer with a cautious estimate from another.

Also check how the energy is used. For a house, what matters most is how much production coincides with consumption. Surplus fed into the grid has a different settlement value from energy consumed on site. A roof cost comparison should therefore include assumptions about the building’s use, not just an annual yield curve.

A steel roof panel with integrated photovoltaics combines functions that, in a traditional arrangement, are performed by two sets of elements. In the active field, no complete conventional covering is created beneath a separate installation. This can reduce some materials and work. However, the scale of the benefit depends on the specific structure and the scope of the order.

Joint planning can also be advantageous organisationally. One scaffold can serve the related stages, and cable routes are created before the interior is finished. Savings should not be entered in advance at a fixed amount. First, the contractor should show which activities actually disappear or are combined in the schedule.

At the purchase stage, it is easy to overlook service access, periodic inspections or the future replacement of electrical equipment. Not all components have the same warranty period. A module power warranty does not mean free repair of the entire roof for the same period. The terms must be read separately for the product, the works and the equipment.

In the comparison, record who locates a fault, how they reach the damaged element and who restores watertightness. The availability of spare parts is also important. It is impossible today to price every future repair exactly. However, an offer that does not describe responsibility and how the installation is serviced can be rejected.

A good comparison shows the initial cost, expected production, own consumption and the assumed maintenance costs. It should also include a less favourable scenario for energy prices or lower yield. This shows whether the conclusion holds after the assumptions change. A single payback period without such a background says little.

Aesthetics and the consistency of the covering also have value for the owner. There is no need to pretend that each of these qualities can be expressed in kilowatt-hours. The architectural effect can be assessed separately from the financial result. A conscious choice takes both reasons into account and does not require a promise that every more expensive technology will always pay back faster.

Examples of companies and brands in roof-integrated photovoltaics are Wienerberger Wevolt, LUMA Solar, Tesla, SunRoof, MDM NT (MyRoof), ML System, Electrotile, Ennogie, SolRoof and Solartag.